Air blown asphalt product



, ing stained and blotched Patented Nov. 7, I933 ENT OFFICE AIR BLOWNASPHALT PRODUCT Morris Levine, Chicago,

Ill., assighor, by mesne assignments, to The Lehon Company, Chicago,

111., a corporation of Illinois No Drawing.- Application January 25,1932

Serial No. 588,838

This invention relates to air-blown asphalt products and a method ofpreventing discoloration of the same.

In the production of air-blown asphalt products, and particularlyasphalt roofing, it is economically desirable to use asphalt producedfrom Mid-Continent residuum. Such asphalt, however, has the undesirablecharacteristic of formareas presenting an unsightly appearance. Forexample, a roofingcomprising the customary roofing base such asasphalt-saturated felt, coated with air-blown'asphalt derivedirom theMid-Continent residuum, and covered with a layer of talc or slate, whensubmitted to the underwriters test, requiring that the roofing be heldvertically for two hours at 180 R, will show, after the test, stains andblotches. This staining is apparently due to the emergence of aseparable oily portion of the asphalt. As a result, asphalts derivedfrom Mid- Continent residuum, although cheaper than asphalt derived fromasphalt base residuums such .as Mexican, are avoided in the manufactureof roofing. Asphalts derived from residuums of the Mid-Continent type,for example, Illinois and Smackover residuums, give rise to the samedimculty.

In accordancewith this invention, the tendency of air-blown asphalts ofthe Mid-Continent type to stain and discolor is avoided by the use of arelatively thin coating of rosin. For erample, roofing material may beproduced-in the customary ,manner by coating an asphalt saturated feltbase with air-blown asphalt of the Mid-Continent type and then placingthereon a layer of crushed slate or talc'with which has been admixed 3to 4% by weight of rosin. The rosin ispreferably comminuted to pass a200 mesh screen and be caught on a 325 mesh screen.

Instead of admixing the rosin with the stone layer, it may be dissolvedin a volatile solvent such as alcohol or benzene and sprayed on thesurface of the asphalt, or it may be mixed with a stable asphalt such asMexican in the proportion of, say, 5 to 20% rosin and preferably 20%,and the roofing coated with a thin layer of the mixture. By stableasphalt is meant asphalts of the type which does not causediscoloration.

A further improvement may be accomplished by adding an inert substanceof higher melt point, such as gilsonite, to the rosin. Soaps, forexample, either sodium or calcium soaps may likewise be used. Thesesubstances preserve the appearance of the roofing under elevatedtemperature conditions better than the rosin alone.

Instead of rosin, the synthetic resin known as teglac, or the coal tarresin cumar, or benzoic acid may be used, but are somewhat lesssatisfactory. Pontianak, Indian gum, congo, abietic acid or gum arabicmay be used in combination with rosin.

' The foregoing detailed description has been given for clearness ofunderstanding only, and no unnecessary limitations should be understoodtherefrom, but the appended claims should be construed as broadly aspermissible, in view of the prior art.

I claim:

1. The method of preventing discoloration, due to Mid-Continent typeair- -blown asphalt, in asphaltic products containing the same, whichcomprises: coating the surface of said asphaltic products with rosin.

'2. The method of preventing discoloration, due to Mid-Continent typeair-blown asphalt, of asphaltic roofing containing the same, whichcomprises: coating, said roofing with a layer comprising crushedstoneand a minor proportion of comminuted rosin.

3. The method as set forth in claim 2 in which the rosin comprises 3 to4% of the crushed stone mixture.

4. The method as set forth in claim 2 in which the rosin is comminutedto such fineness that it will pass a 200 mesh and be caught upon a 325mesh screen.

5. The method of preventing discoloration, due to Mid-Continent typeair-blown asphalt, of asphaltic roofing containing the same, whichcomprises: spraying a solution of rosin in a volatile solvent upon thesurface of said roofing. I

6. The method of preventing discoloration, due to Mid-Continent typeair-blown asphalt, of asphaltic roofing containing the same, whichcomprises: spraying a solution of rosin in a volatile solvent upon thesurface of said roofing, and covering said rosin with a protective layerof crushed stone.

7. The method of preventing discoloration due to Mid-Continent typeair-blown asphalt, or asphaltic roofing containing the same, whichcomprises: coating said roofing with a relatively thin layer comprisinga mixture of rosin and a stable asphalt.

8. The method as set forth in claim 7 in which 106 the rosin constitutes5 to 20% of said rosin and stable asphalt mixture.

' 9. The method of preventing discoloration due to Mid-Continent typeair-blown asphalt of asphaltic roofing containing the same, which com-110 prising a mixture of rosin and a relatively high melt point inertsubstance.

10. The method as set forth in claim 9 in which said mixture comprisesrosin and gilsonite.

11. Asphalt roofing comprising: a roofing base, an air-blown asphalt'ofthe Mid-Continent type coating said base, and a protective layerthereupon comprising a mixture of comminuted rosin and crushed stone.

12. Asphalt roofing as set forth in claim 11 in which the rosincomprises 3 to 4% of the crushed stone mixture.

13; Asphalt roofing as set forth in claim 11 in which the rosin iscomminuted to such fineness that it will pass a 200gmesh screen and becaught upon a 325 mesh screen.

14. Asphalt roofing comprising: a roofing base, an air-blown asphalt ofthe Mid-Continent type coating said base, and a thin layer of rosinthereupon.

15. Asphalt roofing comprising: a roofing base,

prises: coating said roofing with a layer coman air-blown asphalt of theMid-Continent type coating said base, and a protective layer of crushedstone upon said rosin layer.

16. Asphalt roofing comprising: a roofing base, an air-blown asphalt ofthe Mid-Continent type coating said base, and a relatively thin layerthereupon comprising a mixture of rosin and a stable asphalt.

1'7. Asphalt roofing as set forth in claim 16 in which the rosinconstitutes 5 to 20% of said asphalt rosin layer.

18. Asphalt roofing comprising: a roofing base, an air-blown asphalt ofthe Mid-Continent type coating said base, and a layer thereon comprisinga mixture of rosin and a relatively high melt' point inert substance.

19.- Asphalt roofing comprising: a roofing base, an air-blown asphalt ofthe Mid-Continent type coating said base, and a layer thereon comprisinga mixture of rosin and gilsonite.

MORRIS

